Giardia is a ubiquitously distributed flagellate protozoon that inhabits the small intestine of its host. In this paper, Giardia infection is reported in the gall bladder of an adult cow. Faecal samples from asymptomatic dairy cows and calves from several farms in Zara, Sivas, were studied by direct examination and the zinc sulphate flotation techniques. No Giardia cysts were found in 106 samples. In addition, the gall bladders of cattle provided from the slaughterhouse in Sivas were tested by direct and zinc sulphate flotation technique examination. Giardia trophozoites were found in 1.7% of the 56 gall bladders tested. This is the first report of Giardia-infected adult cattle from Turkey. Giardia trophozoites were obtained from fluid and mucosal scrapings from the infected gall bladder. Trophozoites were then cultured in bile-supplemented TYI-S-33 medium and RPM1/1 640 containing 10% foetal calf sera and 1% NCTC 135.